The Washington University facility has a VG ZAB-T four-sector tandem mass spectrometer equipped with an extended array detector. The purpose of the research is to develop this unique instrument for studies of biomolecule structure. Subject molecules are peptides, complex lipids, and carcinogen-modified DNA. Currently under investigation is a comparision of various ionization modes (i.e., electrospray, FAB, and two versions of flow FAB) for the capability to desorb and ionize the various subject molecules. Criteria for success include signal-to-noise, detection limits, and capability to do MS/MS. Future plans include addition of MALDI to the repertoire of ionization methods.